In recent years, powder coatings have become increasingly popular because these coatings are inherently low in volatile organic content (VOC), which significantly reduces air emissions during the application and curing processes. Liquid coatings are still used in many systems, however. For example, the coating of automobiles, including elastomeric automotive parts, household appliances and flooring often is done using liquid coatings.
Topcoats such as the transparent clearcoat in color-plus-clear coating systems for automotive applications and/or other protective and decorative coatings such as for household appliances, are subject to defects that occur during the assembly process and damage from both the environment and normal use of the end product. Paint defects that occur during assembly can include the paint layer being too thick or too thin, “fish eyes” or craters, and under-cured or over-cured paint; these defects can affect the color, brittleness, solvent resistance and mar and scratch performance of the coating. Damaging environmental factors include acidic precipitation, exposure to ultraviolet radiation from sunlight, high relative humidity and high temperatures; these factors can also result in compromised performance. Normal use of consumer products such as appliances and flooring can lead to marring, scratching and/or chipping of the surface due to contact with hard objects, contact with brushes and/or abrasive cleansers during normal cleaning processes, and the like.
Thus, there is a need for coatings having good scratch and mar resistance, while maintaining other coating performance and appearance properties.